Cryogenic fluids are widely used in industrial applications, space exploration, and cryosurgery systems. Specifically, in space exploration, cryogenic fluids are used in the power and propulsion, thermal management, and life-support systems of a spacecraft during space missions. These systems involve transport, handling, and storage of these fluids under both terrestrial and microgravity conditions. For example, cryogens such as liquid hydrogen and oxygen are used as liquid fuels such as that liquid hydrogen and oxygen that are burned in the liquid-fueled rocket engine. When a cryogenic fluid transport system first starts up, its walls and hardware go through a transient chilldown period prior to reaching steady state operation. Chilldown is the process of adjusting the system to the low temperature scale, which is usually several hundred degrees below the room temperature. The chilldown or quenching process is a complicated phase-change phenomenon, involving unsteady two-phase flows, and heat and mass transfer.